Immunoglobulin (lg) therapy is used to treat conditions related to the immune system. In a healthy body, the immune system produces specialized proteins called immunoglobulins or antibodies. The function of these proteins is to fight infections. The three primary types of immunoglobulin therapy are autoimmune therapy, immunodeficiency therapy and inflammatory therapy. Additionally, immunoglobulin therapy can also be used to treat severe, acute infections.
Immunoglobulins are glycoprotein molecules that are formed by white blood cells. These proteins, which circulate throughout the bloodstream, function as antibodies, attacking antigens by binding to them. Antigens are foreign substances within the body that trigger an immunological response, such as bacteria, viruses, toxins, fungi and cancer cells.
One type of immunoglobulin therapy is used for the treatment of autoimmune disorders. These disorders cause the body’s immune system to mistakenly attack and destroy healthy cells, rather than antigens. There are more than 80 types of autoimmune disorders, including Addison’s disease, dermatomyositis, multiple sclerosis and Grave’s disease.
Immunodeficiency therapy is a form of immunoglobulin treatment that is used in cases where the body’s immune system is producing low levels of antibodies. When this condition exists, the body is unable to attack and destroy the antigens that are present. Examples of immunodeficiency disorders include hypogammaglobulinemia, panhypogammaglobulineamia and Bruton disease.
Treatment of inflammatory diseases represents another type of immunoglobulin therapy. These diseases, which are autoimmune in nature, occur when the body mistakenly triggers an inflammatory response in the absence of any antigens. This response can cause painful and debilitating inflammation, typically around joints. Examples of inflammatory diseases include rheumatoid arthritis, tendinitis, bursitis, gouty arthritis and polymyalgia rheumatic.
Intravenous (IV) infusions are the primary means of administering immunoglobulin therapy. These IVs are comprised of extra immunoglobulins that have been collected from donor blood. One dose can contain immunoglobulins from 3,000-10,000 donors. Although immunoglobulin therapy was originally administered via intramuscular injections, research has found that infusions are a more effective means of delivering the treatment.
There are three primary types of immunoglobulins: immunoglobulin-G (lgG), immunoglobulin-A (lgA) and immunoglobulin-M (lgM). Immunoglobulin infusions typically are comprised of more than 95 percent immunoglobulin-G. These antibodies are the smallest and most abundant antibodies, comprising 75 to 80 percent of the body’s antibodies. Immunoglobulin-G proteins are found in all body fluids and are considered the most important immunoglobulins for fighting bacterial and viral infections.
The other two types of immunoglobulin represent less than 5 percent of typical infusions. Immunoglobulin-A is primarily found in locations where body tissues are frequently exposed to antigens, such as the nose, airways, eyes and ears. They also are found in the digestive tract, saliva, tears and vagina. Immunoglobulin-M is found in the blood and lymph fluids, and it is the first antibody produced in response to infections.
Common side effects of immunoglobulin therapy occur in less than 5 percent of patients. These symptoms often include flushing, headaches, chills, dizziness and sweating. They also might include leg cramps, muscle pain, lower back pain and low blood pressure. It is common for the patient to experience some pain at the site of the infusion.
The most serious risk associated with immunoglobulin therapy is a severe and systemic allergic reaction, called anaphylactic shock. This life-threatening condition can produce difficulty breathing, confusion, slurred speech, hives, rashes and itching. It can result in low blood pressure, shock and lowered levels of consciousness.
Severe allergic reactions have been found to occur in approximately one out of every 500-1,000 patients. These reactions typically are associated with lgA-deficient patients who have a heightened sensitivity to immunoglobulin-A. The use of a lgA-depleted immunoglobulin infusions can reduce the risk in these patients.